1. Field of the Invention
The present invention relates to an improvement of an engine for a vehicle, including a bearing cap-integral type oil pan integrally provided with bearing cap sections and coupled to a cylinder block.
2. Description of the Related Art
A conventionally known an engine for a vehicle is disclosed, for example, in Japanese Patent Publication No. 59-50864, in which an oil pan integrally provided with a plurality of bearing cap sections for supporting a crankshaft, is coupled to an end face of a cylinder block on the side of a crank chamber by connecting bolts.
In the above known engine for a vehicle, however, the following problems are encountered: (1) Since the oil pan is fastened to the cylinder block by connecting bolts passing through bolt bores in a bottom wall of the oil pan, seal means are required in the bolt bores, resulting in an increased number of parts. (2) The opening of the bolt bores brings about a reduction in rigidity of the oil pan itself. (3) Since the plurality of bearing cap sections extend to the bottom wall of the oil pan and are integrally connected to the bottom wall, an increase in weight of the oil pan is brought about. (4) The structure of the oil pan itself is complicated, and the mold for forming the oil pan by casting is complicated, resulting in an increased manufacturing cost.